A small pea-sized region of the brain, the habenula is a highly conserved structure across vertebrates. They are found at the stalk base attached to the pineal gland to the diencephalon. The habenula functions as a neuroanatomical hub that connects and regulates several brain regions for divergent motivational states, decision-making, cognition, and sleep. The habenula is divided into two divisions: medial and lateral. It receives information from the limbic system and basal ganglia via the stria medullaris. It subsequently sends information to the dopamine-rich areas of substantia nigra and ventral tegmental area. The habenula also projects to the raphe nuclei, which is serotonin-rich, playing prominent roles in depression and motivation.